My girlfriend said she needs a break........

If she is having mixed emotions, the best thing for you to do is step back and give her time to sort things out. If you refuse to let her do that, she may end up resenting you. If she needs time to figure out what she wants, give it to her. I know that she may be breaking your heart by doing this, but she is doing the best thing, she is being honest with you and she is trying to sort it out. I think that she just needs time to get things thought through and if she comes back to you, it will be a stronger relationship. If she does not, then that is not what she wants and I know that you do not want to be with someone that does not want to be with you, right?
Just let her have her space and let her know that you are there for her.
Good luck to you!